Abstract: The technique of preparing vanillin by oxidation of isoeugenol was optimized through orthogonal test. The yield of crude product was over 55% at the condition of isoeugenol 60 g,reaction time 5 h,oxidant 108 g,32% NaOH solution145 g. The content of vanillin after recrystallization in ethanol was over 99%.The technique could increase the yield of product and purify aroma of product compared with orginal technique.